Exploration of the Evaluation Value of Combined Magnetic Resonance Imaging and Ultrasound Blood Flow Parameters in Cervical Lymph Node Metastasis of Thyroid Cancer.

BACKGROUND

Thyroid cancer exhibits the highest cervical lymph node metastasis rate (20-50%) among head and neck malignancies, with occult metastasis occurring in 30-80% of papillary carcinoma cases. However, conventional single-modality imaging faces certain challenges: MRI has limited sensitivity for detecting micro-metastases (<2mm), while Doppler ultrasound may overlook metastases in isoechoic lymph nodes. Therefore, it is crucial to evaluate the diagnostic value of combining MRI and CDUS. This study aims to retrospectively analyze the diagnostic value of combining MRI and CDUS blood flow parameters in detecting cervical lymph node metastasis in thyroid cancer and to compare the diagnostic performance with MRI or CDUS alone.

OBJECTIVE

To analyze the evaluation value of combining MRI and color Doppler ultrasound (CDUS) blood flow parameters in detecting cervical lymph node metastasis of thyroid cancer, particularly for occult metastases.

METHODS

A retrospective analysis was conducted on 263 thyroid cancer patients (June 2022-June 2024). Diagnostic consistency between MRI, CDUS parameters (resistive index, pulsatility index, vascular patterns) and pathology were compared. Multimodal evaluation criteria were established: (1) MRI positive signs (lymph node diameter >8mm, cystic change, enhancement heterogeneity) (2) CDUS thresholds (RI≥0.75, PI≥1.25 with chaotic vascularity).

RESULTS

Among 263 patients, 98 had pathologically confirmed metastases. CDUS showed higher consistency with pathology (Kappa=0.783) than MRI (Kappa=0.645). Combined modality achieved 94.9% sensitivity vs 86.7% (CDUS) and 78.6% (MRI), with accuracy improving from 82.1%/75.3% to 89.4% (P<0.05). Notably, 12/22 occult metastases (≤3mm) were only detected by combined approach.

CONCLUSION

The synergistic combination leverages MRI's structural characterization and CDUS's hemodynamic sensitivity, effectively overcoming single-modality limitations in detecting micro-metastases. This dual-assessment protocol addresses thyroid cancer's propensity for early lymphatic spread, providing critical preoperative staging guidance.